Abstract

An electrically tunable-focusing optical zoom system using two composite LC lenses with a large zoom ratio is demonstrated. The optical principle is investigated. To enhance the electrically tunable focusing range of the negative lens power of the LC lens for a large zoom ratio, we adopted two composite LC lenses. Each composite LC lens consists of a sub-LC lens and a planar polymeric lens. The zoom ratio of the optical zooming system reaches ~7.9:1 and the object can be zoomed in or zoomed out continuously at the objective distance of infinity to 10 cm. The potential applications are cell phones, cameras, telescope and pico projectors.

Fabrication process of the composite LC lens. (a) Polymerize the isolating layer (b) polymerize the polymeric layer with a curing voltage of 80 Vrms, (c) peel off the bottom substrate, and (d) sandwich the LC between (c) and another glass substrate.

(a)The phase profiles of the LC lens at different voltages. (b) The lens power of the composite LC lens as a function of applied voltage V1 when V2 was 40 Vrms (gray triangles) and the lens power of the composite LC lens as a function of applied voltage V2 when V1 was 80 Vrms (black dots). λ = 532 nm.

The measured magnification as a function of the distance between target and the LC eyepiece lens (or p). The black dots indicate the maximum magnification and the blue triangles indicate the minimum magnification.